Metal powder extrusion of magnetocaloric heat exchanger structures

Metal Powder Extrusion is a very efficient method to produce complex-shaped components. When applying the process to the production of magnetocaloric heat exchanger structures, both the oxygen sensitivity of the magnetocaloric material (LaFeSi-based alloy) and the specifications regarding the geometry (wall thickness <500 mm for optimized heat transfer) impose special challenges to the processing. The study describes the adjustment of the binder and feedstock composition, the tool design and the process parameters to meet these requirements and to assess the smallest wall thickness attainable. The dimensional accuracy, the oxygen and carbon content and the magnetocaloric properties after extrusion, subsequent debinding and sintering are examined.